Table 2 Overview of the inclusion criteria

• Children aged between 6 and 48 months

• Completed parental consent form

• Sleep disturbance diagnosis according to the International Classification of Sleep Disorders [56] and age-related criteria [57]

o Sleep onset disturbance (≥ 2 episodes per week, with two of the three following criteria, over ≥ 4 weeks)

      ♣ Sleep onset latency over 30 min if the child was between 12 and 23 months or over 20 min if the child was older than 24 months

      ♣ Need for the parents in the room to fall asleep

      ♣ Bedtime resistance

o Night waking disturbance (≥ 2 episodes per week, over ≥ 4 weeks)

      ♣ More than two nighttime awakenings if the child was between 12 and 23 months old or more than one if the child was older than 24 months

      ♣ More than 20 min awake during the night